<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .outer {
            /*width: 500px;*/
            /*height: 500px;*/
            background-color: red;
            /*border: 10px solid red;*/
        }

        .inner {
            background-color: gold;
            position: absolute;
            width: 100px;
            height: 100px;
        }

        .inner2 {
            width: 100px;
            height: 100px;
            background-color: green;
            /*position: absolute;*/
            /*clear: both;  */
        }
    </style>
</head>
<body>
<div class="outer">
    <div class="inner">123</div>
    <div style="clear: both"></div>
    <div class="inner2">456</div>
</div>
</body>
</html>